How To Win At The Expense of Allies

This is how i win most whole world, multiple player games. So when you get to a point in the game where it will be determined by SP or amount of troops, look at your allies cities and capitals. If any of them have 0 troops in them, take it. WARNING: I do not suggest doing this if his allies are near with large force or the ally you are taking land from is greater. I won a previous game by SP by taking my allies capitals. It was the last 5 rounds and he somehow gained 200 SP to surpass me in the last 3 rounds. Doing this, with his capital with 0 troops in it, I ended our alliance.By the time he noticed his land and capital was no longer his, it was too late. If this topic stirs any interest i will go deeper into information. Thank you if you made it to this point.

Noted will try on you when we are allied in a game.
In all seriousness you really want to back stab the only ally who was kind enough to work with you?